Collins



Feb. 21, 1956 T. COLLINS STRUCTURAL MEMBER 3 Sheets-Sheet 1 Filed Sept. 9, 1949 INVENTOR TA PPA N COLLINS ATTORNEY Feb. 21, 1956 T. COLLINS STRUCTURAL MEMBER 3 Sheets-Sheet 2 Filed Sept. 9, 1949 INVENTOR TAPPAN COLLINS ATTORNEY Feb. 21, 1956 T. COLLINS STRUCTURAL MEMBER I5 Sheets-Sheet 3 Filed Sept. 9, 1949 INVENTOR TAPPAN COLLINS ATTORNEY United States Patent STRUCTURAL MEMBER Tappan Collins, Grosse Pointe Woods, Mich., assignor to National Steel Corporation, a corporation of Delaware Application September 9, 1949, Serial No. 114,882

13 Claims. (Cl. 189-37) The present invention relates to a novel structural member and to apparatus for and a method of forming such a member from strip metal and particularly relates to an improved structural member adapted to receive and hold nails and to apparatus for and a method of forming such a member from strip metal, such as strip steel.

Elongated nailable structural members have been :proposed that include a longitudinal groove. The groove includes a nail bending recess that is substantially circular in cross section and a restricted entering throat opening into the recess. A relatively small diameter mandrel extends the length of the recess so that when a nail is driven into the groove, the pointed, leading end of the nail passes through the throat into the recess and bends around the mandrel and the nail is held in place by this end which is hooked around the Wire. Nailable structural members of this type have relatively little resistance to being wedged open. When a nail is driven into the groove, the nail tends to wedge open the groove over a relatively long length as there is nothing which localizes the forces exerted by the nail. As a result, the nailable member is only practical in heavy hot rolled sections and insofar as is known, members of this type are not being used.

It is an object of this invention to provide an improved elongated structural member containing a longitudinally grooved portion that is relatively strong and that can be fabricated from relatively thin strip material and to provide an improved method of and apparatus for fabricating such a structural member.

It is an object of the present invention to provide an improved nailable structural member that includes a nail receiving groove of the type in which the nail is bent around a mandrel in the groove, to provide such a nailable structural member that can be fabricated frornrelatively light strip metal, to provide such a nailable member that is so constructed and arranged as to localize the forces exerted by a driven nail tending to spread apart the nailing groove walls, to provide such a nailable member in which the Walls of the nail receiving and bending groove strengthen the member, and to provide a novel apparatus for and method of forming such a nailable structural member.

In accordance with my invention, and after a groove having a straight longitudinal axis has been formed in the strip metal, the Walls defining the groove .are stretched and elongated so that the groove defining portion of the strip is longer than the main body of strip. The longitudinal axis then assumes the form of a wavy line instead of a straight line. Preferably, successive lengths of the elongated groove are alternately displaced in opposite lateral directions from the original axis so that the longitudinal axis of the groove assumes the shape of -a sinusoidal curve. The walls of the nailing groove are strengthened against spreading and the forces exerted by a nail driven into the groove are localized. In addition, the curved grooved portion strengthens the member, and the member may be formed from relativelylight or thin sheet metal,

. such as strip steel.

These and other objectsand advantages will become more apparent from the following description, taken with the accompanying drawings, in which:

Figure 1 is a side view diagrammatically illustrating one form of apparatus embodying the principles of the present invention for producing my novel structural member;

Figure 2 is a plan viewof the apparatus of Figure 1;

Figure 3 is a cabinet view, with portions removed, of the apparatus of Figure 1;

Figures 4, 5 and '6 are sectional views taken along line 4-4 of Figure 2 and illustrating different steps in the shaping of the grooved portion;

Figure 7 is an enlarged fragmentary sectional view showing a nail in place; and

Figures 8 to 11, inclusive, each illustrate various shapes embodying the principles of the present invention.

Referring to the drawings and more particularly to Figures 1 to 7, inclusive, the apparatus diagrammatically shown is for forming a-nailable member from an elongated strip of sheet S which includes a longitudinal midportion 10 defining an open longitudinal groove 11. The mid-portion 10 integrally joins the spaced, coplanar side portions 12 and 13 so that the elongated strip S consists of a longitudinal mid-portion 10 which is laterally displaced from the plane of the strip and which defines a groove 11 and a coplanar longitudinal side portion integrally joined to each lateral edge of the mid-portion 10. The groove '11 may be formed by any suitable means and in any suitable manner.

The apparatus for shaping the strip S includes a stretcher roll 15 and two tensioning means 16 and 17 arranged so that thestrip S passes through an are about a portion of the periphery of the stretcher roll 15. The tensioning or drag means 16 includes a pair of rolls 19 and 20 rotatably mounted on shafts 21 and 22, respectively, and adapted to engage the opposite surfaces of the strip S. Any suitable means, such as a brake or generator (not shown), may be connected to shafts 21 and 22 to apply drag to the rolls 19 and 20 so that the rolls 19 and 2t resist movement of the strip toward the stretcher roll 15. The tensioning or pull means 17 also includes a pair of power actuated rolls 23 and 24 rotatably mounted on shafts 25 and 26. Any suitable power means, such as a motor (not shown) may be attached to shafts 23 and 26 for rotating the rolls for pulling the strip S. Tensioning means of various types are well known and are customarily used around steel mills for moving strip under tension along a path. 'With the pull means 17 pulling the strip S with 'sufiicient force to move it past the drag means 16 and the stretcher means 15, the strip S is moved in the direction indicated by arrows under heavy tension.

The stretcher means or ro'll15 includes a mid-portion 28 of relatively large diameter that fits into the groove 11 of the grooved mid-portion 10 of the strip S. Shoulder portions'29 and 30 extend laterally from the sides of the midportion for engaging-the surfaces of the corresponding side portions 13 and 12. With this arrangement, the strip S is continuously'moved through an are about the stretcher roll 15. As the groove fitting mid-portion 28 has a radius larger than the shoulders 29 and 30 by a distance equal to the depth of groove 11, the groove defining mid-portion It) of the strip extends outwardly from side portions 12 and 13 and the mid-portion 10 moves through an arc of greater diameter and a longer path than the side portions 12 and 13. The side portions 12 and 13 are under tension so that they cannot buckle, and the bending of the strip S about the stretcher roll under tension stretches the groove defining mid-portion 1.0 with :the peak 32 being stretched the most. It will be noted that the tensioning rolls do not directly grip the grooved mid-portion 10.

When the strip S with the stretched or elongated mid portion passes the stretcher means, the strip moves along a straight path toward the drag rolls 23 and 24. When the strip S is straightened after the groove-defining portion 10 has been stretched, the portion 10 buckles as it is longer than portions 12 and 13. The portion when it buckles assumes a wavy shape with successive lengths laterally displaced in alternately opposite directions. The rib or groove defining portion assumes a wavy shape, that is, the longitudinal axis instead of being a straight line as it is originally becomes a wavy or irregular line because it has been elongated. This waviness or lateral displacement increases the strength of the grooved portion. Preferably, this waviness is controlled so as to provide the maximum increase in strength by positively laterally displacing successive equal lengths in alternately opposite directions so that the longitudinal axis of the groove assumes a sinusoidal curve.

Between the stretcher roll 15 and the pull tension means 17, there is means for laterally displacing successive equal lengths of the lengthened grooved portion 10 in alternately opposite directions. A rotatable eccentric roll 36 is mounted on a shaft 37 which is normal to the portion 12. Similarly, an eccentric roll 38 is mounted on shaft 39. Both rolls 36 and 38 are arranged to engage therebetween the opposite sides of the grooved portion 10. The rolls 36 and 38 are proportioned and arranged so that the distance between their closest points 44) and 41 remains substantially constant and the sum of their radii between their axes is substantially constant. With this arrangement and upon movement of strip S between and past the rotating rolls 36 and 38, the space between the rolls moves back and forth equal distances from a point midway between the centers of the rolls and the metal is moved back and forth laterally. In other words, the rolls control the lateral displacement of portion 10 so that successive equal lengths are displaced in alternately opposite directions. As shown in Figure 3, portion 42 is displaced to the left, portion 43 is displaced to the right, and portion 44 is displaced to the left. These portions are of equal length. Without the rolls 36 and 33, the grooved portion would be wavy or corrugated but the waves or corrugations would not be uniform with the result that the resistance to spreading would not be uniformly increased along the length of the strip.

When passing around the stretcher roll, the groove 11 is wide open and the sides 46 and 47 are either parallel or flared outwardly so that the entrance 4% defined by the shoulders 49 and 50 is as wide or wider than any other portion of the groove 11 to permit entrance of the large roll 28. After the grooved portion has been stretched and elongated, the shoulders 49 and 50 must be brought towards each other to restrict the throat 48. Preferably, but not necessarily, this is done when the elongated portion is laterally displaced. As shown more particularly in Figures 4- to 6, on the lower ends of each of shafts 37 and 39 there is mounted a roll 52 and 53, respectively. Rolls 52 and 53 are rotatable independently of rolls 36 and 38 as the rolls do not rotate at the same angular velocity. The angular velocity of rolls 5?. and 53 is constant, whereas the angular velocity of rolls 36 and 38 varies. Thus, of each pair of rolls 36 and 52 or 38 and 53, at least one roll is rotatable independently of the corresponding shaft, and the two rolls are supported for rotation independently of each other. Separate shafts may be provided for each pair of rolls.

The squeeze rolls 52 and 53 squeeze the shoulders inwardly toward each other to reduce the throat 48 to a relatively narrow width that is approximately the same width as the diameter of the nail to be driven into the groove. Squeezing the shoulders together causes the remaining portion of the groove 11 to assume a substantially circular shape and define a slot or recess 55 that is circular or rounded in cross-section. In Figure 4, the parts are shown in the position assumed when the grooved portion is centrally positioned, and in Figures 5 and 6 the parts are shown in the positions assumed when the grooved portion is displaced to the left and when the grooved portion is displaced to the right, respectively. It will be noted that after the grooved portion has been shaped, the groove 11 includes a substantially circular slot or recess 55 and a restricted entry throat 48.

A mandrel or wire 56 is provided in the slot 55. This mandrel 56 may be inserted at any time, preferably before the shoulders are squeezed together. The groove engaging roll 28 contains a slot 57 extending about its periphery and the wire 56 fits this slot. The strip S and wire 56 are simultaneously fed past the stretcher roll 15 so that the wire is in place when the rolls 52 and 53 reduce the throat 48. The wire 56 floats in the slot 55. While stretching and lateral displacement of the grooved portion 10 tends to cause the grooved portion to grip the wire at spaced points along its length, the wire fioats and will assume a central position in the slot when a nail is driven into the slot. The diameter of wire 56 is smaller than the diameter of the slot 55, and the difference in these diameters, preferably, is substantially equal to the width of throat 48 and substantially equal to the diameter of the nail driven into the slot so that the wire and slot together define a reentrant nail receiving groove.

In accordance with the present method of forming a structural member from an elongated strip S having a longitudinal grooved mid-portion 1t? joining coplanar opposite edge portions 12 and 13, the mid-portion 10 is elongated relative to the edge portions. Preferably, the elongating of mid-portion 10 is effected by passing the grooved strip through an arcuate path while under tension and with the grooved portion extending outwardly so that the grooved portion 10 passes through the longer path. Then successive lengths of the lengthened midportion are laterally displaced in alternately opposite directions. The shoulders 49 and 50 are squeezed together and a wire 56 is placed in the groove before or after the shoulders are squeezed together.

Referring to Figure 7, the resulting elongated nailable structural member 58 is adapted to receive and hold nails for fastening thereto other members, such as a board 59. When a nail 60 is driven through the board, the leading end portion 61 of the nail after passing through the board and through the entering throat 48 enters the slot 55. The wire 56 centers in the slot 55 and the leading end of the nail then passes through the reentrant groove 62 defined by the opposed spaced surfaces of the wire and the wall of slot 55. As the leading end portion 61 of the nail passes through groove 62, it is bent around the wire 56 so that the nail is held in place. The

forces required to bend the nail tend to deform the walls of the groove and tend to spread apart the shoulders 49 and 50. Spreading apart of the shoulders 4) and 50 would weaken the structure, and if these shoulders are spread very much, the nail holding properties are lost. Stretching and laterally displacing the walls of the nailing groove strengthens the member against spreading of the walls and increases the loading capacity of the entire member.

When the grooved portion is stretched the peak 32 of the grooved portion is lengthened or stretched the most while the shoulders 49 and 50 are stretched the least. The throat or slot 48 which extends the length of the strip will be substantially straight while the peak 32 will have the greatest lateral curvature. The longitudinal axis of the nailing groove will curve back and forth somewhat less than the peak 32.

The present method of elongating the grooved portion relative to the coplanar side portions has been shown and described for nailing grooves of the type which include a substantially circular nail receiving slot and a restricted throat opening into the slot. The present in- '5 vention is not limited to this exact shape or :nail receiving slots which include a mandrel.

The strip S after being formed into a nail receiving member may be used without further modification as shown in Figure 7. The nailable member 58 may be additionally modified or may be combined with other members to form the desired type of structural members. Figures 8 to 11 illustrate other shapes also embodying the principles of the present invention. Each of these shapes is formed in accordance to the previously described method, that is, a strip including coplanar side portions joined by a grooved mid-portion has the grooved mid-portion elongated to produce a nailable structural member like that shown in Figure 7 in which the coplanar shoulders are the same width as or a different width than shoulders 12 and 13. The shoulders 12 and 13 may be subsequently bent or formed to the desired shape.

Referring more particularly to Figure 8, this elongated nailing member 65 includes a longitudinally grooved portion 66 formed as previously described with side portions 67 and 63. Each side portion '67 and 68 includes a lateral shoulder portion 69 extending along the corresponding side of the grooved portion 66 and a web portion 74 extending laterally downwardly from the shoulder portion 69 and terminating in a flange '71 extending laterally-outwardly. After the nailable member 65 has been formed with the side portions 67 and 68 coplanar, the side portions 67 and 68 are formed or bent to the shape shown.

Figure 9 illustrates a nailable member 73 having 'two longitudinal nailing grooves 74 and 75 joined by a midportion 76. Coplanar side portions 77 and 78 extend along opposite sides ofthe member 73.

in Figure 10, there is shown a nailable member 79 that includes three nailing groove defining portions 81, 82, and 83. Grooved portions 81 and 82 are joined by an elongated web 84 and grooved portions 82 and 83 are joined by an elongated web 85. Lateral shoulders or flanges 36 and '87 extend along the outer sides of grooved portions 81 and 83, respectively. The grooved portions were elongated While the side portions 86 and 87 and the webs 84 and '85 were coplanar. The webs 84 and 85 were then bent alongli'n'es'88 and 89; respectively, to form the generally U-shaped member 79 having a grooved portion adapted 'to receive the grip nails along each flange and at least one grooved portion 82 extending longitudinally ofthe web'of-the U-s'hap'ed member.

Figure 11 illustrates a compositestructural member 90 made up of a U-s'haped'member '91 and two similar L- shaped members 92 and 93. The LI-shaped member 91 includes a web portion 94 with lateralfi'anges 95' and 96 along each side. Each lateral flange 95 and 96 includes a grooved portion 97. Each L-s'haped member 92 and 93 includes a leg 99 and a leg 100. Each leg 100 includes grooved portion 101 The legs '99 are joined to web 94 by spots welds or other suitable means to form a generally H-shaped member.

In each of Figures 9 to 11, theone or more grooved portions defining anailing groove is formed as described with reference to Figures 1 to 7. When producing-the members 73, 79'and '91, apluralityof grooved portions are simultaneously stretched; When a grooved portion or portions is stretched, the strip is substantially cplanar with the webs or side p'ortions allcoplanarandonly the groovedportion or portions is-displacedlaterallyfrom the plane of the strip.

The present method is not limited to the present apparatus shown and described'in detail. Guidemeansother than roll may be used for guiding the grooved strip through an arcuate path with groovedportion '10 extending outwardly from the sidep'ortions 12 and 13 relative to the axis of the arcuatepath. Other types of tensio'ning 6 means may be usedfor moving'thestrip past me-stretcher means under tension, I j V I The strip metal may be any suitable metal and maybe, for example, hot or cold rolled strip. The strip,after formation of the nailing groove, may be heat treated and hardened. A high tensile low alloy steel may be used.

I claim: M

1. An elongated nailable structural member formed from a single piece of sheet material comprisinglaterally spaced longitudinally extending side .portions presenting spaced longitudinal adjacent edges; a longitudinally extending grooved portion integrally connecting the side portions; the longitudinally extending grooved portion including a pair of spaced longitudinally extending shoulder portions integrally joined along their longitudinal edges to the adjacent longitudinal edges of the side portions and extending outwardly in the same direction from the side portions, and a curved portion having spaced longitudinally extending edges integrally joined to the shoulder portions; the curved portion forming a nail-receiving slot and the spaced shoulder portions defining a-restricted throat opening extending from between the side portions into the nail-receiving slot; successive lengths of the curved portion being laterally displaced alternately in opposite directions with the longitudinal axis of the nail-receiving slot being laterally displaced alternately in opposite directions with respect to'a plane passing through the throat substantially intermediate the shoulder portions, the plane being substantially perpendicular to a second plane passing through the longitudinal edges of the shoulder portions.

2. An elongated 'nailable structural member formed from a single piece of sheet material comprising laterally spaced longitudinally extending side portions presenting spaced longitudinal adjacent edges; a longitudinally extending grooved portion integrally connecting the side portions; the longitudinally extending grooved portion including apair of spaced longitudinally extending shoulder portions integrally joined along their longitudinal edges to the adjacentlongitudina'l edges of the side portions and extending outwardly in the same direction from the side portions, and a curved portion having spaced longitudinally extending edges integrally joined to the shoulder portions; the curved portion forming a nail-receiving slot and the spaced shoulder portions defining'a restricted throat opening extending from the spaced adjacent edges of the side portions into the nail receiving slot; successive equal lengths of the curved portion being laterally displaced alternately in opposite directions with the longitudinal axis of the nail receiving slot being laterally displaced alternately in opposite directions with respect to a plane passing through the throat parallel to the longitudinal edges of the side portions and substantially intermediate the shoulder portions, the plane being substantially perpendicular to a second plane passing through the longitudinal edges of the shoulder portions.

3. An elongated nailable structural member formed from a single piece of sheet material comprising a pair of laterally spaced longitudinally extending coplanar side portions presenting spaced substantially parallel longitudinally extending adjacent linear edges; a longitudinally extending grooved portion integrally connecting-the coplanar side portions; the longitudinally extending grooved portion including a pair of spaced longitudinally extending shoulder portions each having fir stand second longitudinal edges, the shoulder portions being integrally joined along their first longitudinal edges'to the adjacent linear edges of the side portions and extending outwardly inthe same direction from respective side portions, and a curved portion having spaced longitudinally extending edges-integrally joined to the second longitudinal edges of the shoulder portions; the curved portion forming a'n'ailreceiving slot and the spaced shoulder portions defining a restricted throat opening extending longitudinally of the member from the spaced substantially parallel longitudinally extending adjacent linear edges of the coplanar side portions into the nail-receiving slot; successive equal lengths of the curved portion being laterally displaced alternately in opposite directions with the longitudinal axis of the nail-receiving slot being laterally displaced alternately in opposite directions with respect to a plane substantially perpendicular to the coplanar side portions and passing through the throat substantially intermediate the shoulder portions and substantially parallel to the spaced linear edges of the side portions.

4. An elongated nailable structural member formed from a single piece of sheet material comprising a pair of laterally spaced longitudinally extending side portions presenting spaced longitudinally extending adjacent edges; a longitudinally extending grooved portion integrally connecting the side portions; the longitudinally extending grooved portion including a pair of spaced longitudinally extending shoulder portions each integrally joined along their longitudinal edges to the adjacent edges of the side portions and extending outwardly in the same direction from the side portions, and a curved portion having spaced longitudinally extending edges integrally joined -to the shoulder portions; the curved portion forming a nail-receiving slot and the spaced shoulder portions defining a restricted throat opening extending from between the side portions into the nail-receiving slot and extending longitudinally of the member; successive lengths of the curved portion being laterally displaced alternately in opposite directions with the longitudinal axis of the nail-receiving slot being laterlally displaced alternately in opposite directions with respect to a plane passing through the throat substantially intermediate the shoulder portions, the plane being substantially perpendicular to a second plane passing through the longitudinal edges of the shoulder portions; and a mandrel positioned within the curved portion and extending longitudinally of the nail-receiving slot, the mandrel having a cross-sectional area less than the cross-sectional area of the nail-receiving slot to provide a space between the mandrel and the curved portion, the mandrel and the curved portion together defining a re-entrant nail-bending passage so that upon a nail being driven through the throat into the nailreceiving slot the leading end of the nail enters the space .between the mandrel and the curved portion and is bent ,necting the coplanar side portions; the longitudinally extending grooved portion including a pair of spaced longitudinally extending shoulder portions each having first and second longitudinal edges, the shoulder portions being integrally joined along their first longitudinal edges to the adjacent edges of the side portions and extending outwardly in the same direction from the side portions, and a curved portion having spaced longitudinally extending edges integrally connected to the second longitudinal edges of the shoulder portions; the curved portion forming a nail-receiving slot and the spaced shoulder portions defining a restricted throat extending longitudinally of the member from between the side portions into the nailreceiving slot; successive equal lengths of the curved .portion being laterally displaced alternately in opposite directions with the longitudinal axis of the nail-receiving slot being laterally displaced alternately in opposite directions with respect to a plane passing through the throat substantially intermediate the shoulder portions, the plane being substantially perpendicular to a second plane passing through the first longitudinal edges of the shoulder portions; and a mandrel positioned within the curved portion and extending longitudinally of the nail-receiving slot, the mandrel having a cross-sectional area less than 'the cross-sectional area of the nail-receiving slot to provide aspace between the mandrel and the curved portion, the mandrel and the curved portion together defining a re-entrant nail-bending passage so that upon a nail being driven through the throat into the nail-receiving slot the leading end of the nail enters the space between the mandrel and the curved portion and is bent around the mandrel.

6. An elongated nailable structural member formed from a single piece of sheet material comprising laterally spaced longitudinally extending side portions presenting spaced longitudinally extending adjacent edges; a longitudinally extending grooved portion integrally connecting the side portions; the longitudinally extending grooved portion including a pair of spaced longitudinally extending shoulder portions integrally joined along their longitudinal edges to the adjacent edges of the side portions and extending outwardly in the same direction from the side portions, and a curved portion of substantially circular shape having spaced longitudinally extending edges integrally joined to the shoulder portions; the curved portion forming a nail-receiving slot and the spaced shoulder portions defining a restricted throat extending longitudinally of the member from between the side portions into the nail-receiving slot; successive lengths of the curved portion being laterally displaced alternately in opposite directions with the longitudinal axis of the nailreceiving slot being laterally displaced alternately in opposite directions with respect to a plane passing through the throat substantially intermediate the shoulder portions, the plane being substantially perpendicular to a second plane passing through the longitudinal edges of the shoulder portions; and a mandrel positioned within the curved portion and extending longitudinally of the nail-receiving slot, the mandrel being of substantially circular shape and having a cross-sectional area less that the cross-sectional area of the nail-receiving slot to provide a space between the mandrel and the curved portion for receiving a nail driven through the throat into the nail-receiving slot, the mandrel and the curved portion together defining a reentrant nail-bending passage so that upon a nail being driven through the throat into the nail-receiving slot the leading end of the nail enters the space between the mandrel and the curved portion and is bent around the mandrel.

7. An elongated nailable structural member formed from a single piece of sheet material comprising a pair of laterally spaced longitudinally extending coplanar side portions presenting spaced substantially parallel longitudinally extending adjacent edges; a longitudinally extending grooved portion integrally connecting the coplanar side portion; the longitudinally extending grooved portion including a pair of spaced parallel longitudinally extending shoulder portions each having first and second longitudinal edges, the shoulder portions being integrally joined along their first longitudinal edges to the adjacent edges of the side portions and extending outwardly in the same direction from the side portions, and a curved portion having spaced longitudinally extending edges integrally joined to the second longitudinal edges of the shoulder portions; the curved portion forming a nail-receiving slot and the spaced shoulder portions defining a restricted substantially linear throat extending from between the coplanar side portions into the nail-receiving slot longitudinally of the member; successive equal lengths of the curved portion being laterally displaced in alternately opposite directions with the longitudinal axis of the curved portion being laterally displaced alternately in opposite direction with respect to a plane substantially perpendicular to the coplanar side portions and passing through the throat substantially intermediate the shoulder portions and substantially parallel to the spaced adjacent edges of the side portions; and a mandrel positioned within the curved portion extending longitudinally of the nail-receiving slot, the mandrel having a cross-sectional area less than the cross-sectional area of the nail-receiving masses:

slot to provide. a spacebetween. the mandrel and the curved portion, the mandrel and the curved portion: together defining a re-entrant nail-bending passage: so that upon a nail being driven through the throat into the nailreceiving slot theleading end. oi the nail: entersthe space between the mandrel and the curved portion and is bent around the mandrel.

8. An. elongated nailable structural member formed from sheet material comprising supporting meansincluding laterally spaced longitudinally extending sideportions presenting spaced longitudinally extending adjacent edges; a longitudinally extending-grooved portionintegrally connecting the side portions; the longitudinally extending grooved portion including apair of spaced longitudinally extending shoulder portions integrally joined along their longitudinal edges to the adjacent edges of the side portions and extending outwardly in the same direction from the side portions, and a curved portion having spaced longitudinally extending edges integrally joined to the shoulder portions; the curved portion forming a nail-receiving slot and the spaced shoulder portions defining a restricted throat extending from between the side portions into the nail-receiving slot longitudinally of the member; successive lengths of the curved portion being laterally displaced alternately in opposite directions with the longitudinal axis of the nail-receiving slot being laterally displaced alternately in opposite directions with respect to a plane passing through the throat substantially intermediate the shoulder portions, the plane being substantially perpendicular to a second plane passing through the longitudinal edges of the shoulder portions; and web means connected to the supporting means.

9. An elongated nailable structural member formed from a single piece of sheet material comprising laterally spaced longitudinally extending side portions presenting spaced longitudinally extending adjacent edges; a longitudinally extending grooved portion integrally connecting the side portions; the longitudinally extending grooved portion including a pair of spaced longitudinally extending shoulder portions integrally joined along their longitudinal edges to the adjacent edges of the side portions and extending outwardly in the same direction from the side portions, and a curved portion having spaced longitudinally extending adjacent edges integrally connected to the shoulder portions; the curved portion forming a nail-receiving slot and the spaced shoulder portions defining a restricted throat extending from between the side portions into the nail-receiving slot longitudinally of the member; successive lengths of the curved portion being laterally displaced alternately in opposite directions with the longitudinal axis of the nail-receiving slot being laterally displaced alternately in opposite directions with respect to a plane passing through the throat substantially intermediate the shoulder portions, the plane being substantially perpendicular to a second plane passing through the longitudinal edges of the shoulder portions; a mandrel positioned within the curved portion and extending longitudinally of the nail-receiving slot, the mandrel having a cross-sectional area less than the cross-sectional area of the nail-receiving slot to provide a space between the mandrel and the curved portion, the mandrel and the curved portion together defining a re-entrant nail-bending passage so that upon a nail being driven through the throat into the slot the leading end of the nail enters the space between the mandrel and the curved portion and is bent around the mandrel; the web members connected along the other longitudinal edges of the side portions and depending outwardly from the side portions.

10. An elongated nailable structure as defined in claim 9 including angularly disposed flange portions connected to the web members.

11. An elongated metal structural member adapted to receive and hold nails comprising in combination two longitudinally extending grooved portions, a web joining the tions,. the: curved portion formingza nail-receiving slot and.

the spaced shoulder portions defining a restricted: throat: opening extending into; the nail-receiving slottlongitudiw nally of the'mem-ber; successive-lengths of the curvedrpor tion being laterally displaced alternately in opposite direce tions with the longitudinal axis of the nail-receiving slot 5 being laterally displacedi alternately inopposite-directions with respect to av plane passing; through the throat substantially intermediate the shoulder portions, the plane being substantially perpendicularto a second planepass ing through the longitudinal edges of the shoulder portions; and a mandrel positioned within the curved portion and extending longitudinally of the nail-receiving slot, the mandrel having a cross-sectional area less than the crosssectional area of the nail-receiving slot to provide a space between the mandrel and the curved portion, the mandrel and the curved portion together defining a re-entrant nailbending passage so that upon a nail being driven through the throat into the nail-receiving slot the leading end of the nail enters the space between the mandrel and the curved portion and is bent around the mandrel.

12. A U-shaped elongated channel member including a web and an integral flange along each edge of the web, the web and each flange including a longitudinally extending grooved portion, each longitudinally extending grooved portion including a pair of spaced longitudinally extendtending shoulder portions and a curved portion having spaced longitudinally extending edges integrally joined to the longitudinal edges of the shoulder portions, the curved portion forming a nail-receiving slot and the spaced shoulder portions defining a restricted throat opening into the nail-receiving slot and extending longitudinally of the member; successive lengths of the curved portion being laterally displaced alternately in opposite directions with the longitudinal axis of the nail-receiving slot being laterally displaced alternately in opposite directions with respect to a plane passing through the throat substantially intermediate the shoulder portions, the plane being substantially perpendicular to a second plane passing through the longitudinal edges of the shoulder portions; and a mandrel positioned within the curved portion and extending longitudinally of the nail-receiving slot, the mandrel having a cross-sectional area less than the cross-sectional area of the nail-receiving slot to provide a space between the mandrel and the curved portion, the mandrel and the curved portion together defining a re-entrant nail-bending passage so that upon a nail being driven through the throat into the nail-receiving slot the leading end of the nail enters the space between the mandrel and the curved portion and is bent around the mandrel.

13. An H-shaped elongated channel member including a web and an oppositely directed pair of flanges along each edge of the web, each flange including a longitudinally extending mid-portion integrally joined thereto, the longitudinally extending mid-portion including a pair of spaced longitudinally extending shoulder portions and a curved portion having spaced longitudinally extending edges integrally joined to the longitudinal edges of the shoulder portions, the curved portion forming a nail-receiving slot and the spaced shoulder portions defining a restricted throat opening into the nail-receiving slot and extending longitudinally of the member; successive lengths of the curved portion being laterally displaced alternately in opposite directions with the longitudinal axis of the nail-receiving slot being laterally displaced alternately in opposite directions with respect to a plane passing through the throat substantially intermediate the shoulder portions,

the plane being substantially perpendicular to a second plane passing through the longitudinal edges of the shoulder portions; and a mandrel positioned-within the curved portion and extending longitudinally of the nail-receiving slot, the mandrel having a cross-sectional area less than the cross-sectional area of the nail-receiving slot to provide a space between the mandrel and the curved portion, the mandrel and the curved portion together defining a reentrant nail-bending passage so that upon a nail being driven through the throat into the nail-receiving slot the leading end of the nail enters the space between the mandrel and the curved portion and is bent around the mandrel.

References Cited in the file of this patent UNITED STATES PATENTS 338,059 Gocht Mar. 16, 1886 12 Rude Aug. 15, Day Nov. 14, Smith May 5, Budd Feb. 22, Baxter Oct. 11, Harrison Jan. 17, Price May 30, Lind et al. Mar. 20, Smith June 8, Hall Dec. 28, Macomber Dec. 28, Fischer et a1. Mar. 21, Shumaker Jan. 23,

FOREIGN PATENTS France Ian. 16, France Sept. 20, 

